A small amount of base is added to an acidic solution and pH changes from 2 to 3. What is the correct conclusion?
Answer and explanation
Correct answer: Acidity decreased, but the solution is still acidic
The pH scale describes hydrogen-ion concentration, and a neutral solution has pH 7 at ordinary school-level treatment. A rise from pH 2 to pH 3 means the hydrogen-ion concentration has decreased by a factor of ten, so the solution has become less acidic. However, pH 3 is still below 7, meaning it remains acidic. Thus A is correct; B would require pH above 7, C reverses the ion change, and D ignores the measured change.
Frequently asked questions
What is the correct answer to this question?
Acidity decreased, but the solution is still acidic
Why is this the correct answer?
The pH scale describes hydrogen-ion concentration, and a neutral solution has pH 7 at ordinary school-level treatment. A rise from pH 2 to pH 3 means the hydrogen-ion concentration has decreased by a factor of ten, so the solution has become less acidic. However, pH 3 is still below 7, meaning it remains acidic. Thus A is correct; B would require pH above 7, C reverses the ion change, and D ignores the measured change.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Acids, Bases, and Salts.
